Author Question: How was the style of plate tectonics different in the Archean than it is today? When did the present ... (Read 27 times)

vinney12

  • Hero Member
  • *****
  • Posts: 586

How was the style of plate tectonics different in the Archean than it is today? When did the present
  style of plate tectonics begin? What will be an ideal response?



Question 2

What is the origin of greenstone belts? What will be an ideal response?



Jossy

  • Sr. Member
  • ****
  • Posts: 336
Answer to Question 1

Earth in the Archean was much hotter than it is today because Earth's radiogenic heat production was
much higher; in other words, many radiogenic isotopes have decayed to stable daughters and no longer
give off heat. With more heat available, seafloor spreading and plate movements took place more
rapidly. The current plate tectonics style began by the Paleoproterozoic.



Answer to Question 2

Greenstone belts developed in back-arc marginal basins that open and then close. When the basin
opens, volcanism and sedimentation take place, and then the basin closes during a period of
compression. During closure, the rocks are intruded by plutons and metamorphosed, and the
greenstone belt is folded into a syncline and also faulted.




Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
 

Did you know?

More than 20 million Americans cite use of marijuana within the past 30 days, according to the National Survey on Drug Use and Health (NSDUH). More than 8 million admit to using it almost every day.

Did you know?

According to research, pregnant women tend to eat more if carrying a baby boy. Male fetuses may secrete a chemical that stimulates their mothers to step up her energy intake.

Did you know?

The people with the highest levels of LDL are Mexican American males and non-Hispanic black females.

Did you know?

Vaccines prevent between 2.5 and 4 million deaths every year.

Did you know?

Malaria was not eliminated in the United States until 1951. The term eliminated means that no new cases arise in a country for 3 years.

For a complete list of videos, visit our video library